Method of manufacture of an oil seal ring having dual scraper elements for rotary piston mechanisms

ABSTRACT

The method of fabricating an oil seal ring, having dual, concentrically spaced, scraper edges, for use in a rotary piston mechanism, comprises the step of placing a metal blank in a combination coining and punching device and thereafter actuating the latter to engage and deform the sheet material and substantially simultaneously punch out concentric, spaced portions of the sheet to form the inner and outer peripheral surfaces of the ring and an inner annular scraper edge and an outer annular scraper edge defined by a partial shearing of the metal blank.

United States Patent Gavrun 1 June 20, 1972 METHOD OF MANUFACTURE OF AN OIL SEAL'RING HAVING DUAL SCRAPER ELEMENTS FOR ROTARY PISTON MECHANISMS Michael T. Gavrun, Bayonne, NJ.

Curtlss-Wright Corporation April 26, 1971 Inventor:

Assigneez.

Filed:

Appl. No.:

U.S. Cl ..29/l56.61, 29/1566, 72/335, I 72/336 Int. Cl ..B23p 15/06 Field of Search ..29/l56.6, 156.61, 156.62; 277/81 R, 231, 165; 418/142, 94; 72/335, 336, 360

References Cited UNITED STATES PATENTS Week, Jr ..29/l56.6l

2,305,064 12/1942 Colwelletal. ..72/236 3,400,939 9/1968 Jones ..4l8/l42X Primary Examiner-John F. Campbell Assistant Examiner-Victor A. Di Palma Attorney-Arthur Frederick and Victor D. Behn ABSTRACT portions of the sheet to form the inner and outer peripheral surfaces of the ring and an inner annular scraper edge and an outer annular scraper edge defined by a partial shearing of the metal blank.

4 Claims, 4 Drawing Figures INVENTOR.

flaw/1:4 Z 6A VIPUN ATTORNEY METHOD OF MANUFACTURE OF AN OIL SEAL RING HAVING DUAL SCRAPER ELEMENTS FOR ROTARY PISTON MECHANISMS DISCLOSURE The invention relates to a method of fabricating oil seal rings for rotary piston mechanisms, and more specifically, a method of producing oil seal rings having dual, concentric scraper blades or edges.

BACKGROUND OF THE INVENTION In rotary piston mechanisms, particularly internal combustion engines, as exemplified in the United States patents to Bentele, U.S. Pat. No. 3,171,590 and Jones, U.S. Pat. No. 3,400,939, oil seal ring assemblies are carried in the side faces of the rotor or piston, inwardly of the gas seal strips, to minimize the escape of lubricating oil from the region of the rotor shaft gearing. It was found, as shown in the aforesaid patents, desirable to provide an oil seal ring assembly having two concentrically spaced, annular scraper lips or edges which abut the adjacent housing end wall substantially along a circular line. Such oil seal ring assemblies require a considerable number of relatively accurate machining and assembly steps to fabricate. In addition, the insertion of the seal ring assemblies in the rotors in the course of assembly of the engines is difficult because of the multiplicity of components comprising the seal ring assemblies.

Accordingly, it is an object of this invention to provide a method of fabricating a seal ring assembly, having dual, concentrically spaced, scraper edges, which method is relatively simple and inexpensive and wherein both scraper edges are formed in the same body.

In a rotary piston mechanism of the type under consideration, it has been discovered that oil seal ring assemblies, even those having dual, concentric, scraper lips, rock or pivot on the sealing lips or edges due to the distortions of the seal ring assembly and engine housing under varying conditions of centrifugal loads, fluid pressure and frictional drag on the seal ring assembly and thermal stresses on the housing. 'Accordingly, it can be anticipated that some oil leakage past the outermost scraper lip will occur. Therefore, it is desirable to provide means for returning at least some of the leakage oil back past the scraper lip into the annular space between the two scraper lips.

It is, therefore, another object of the present invention to provide a method of fabricating oil seal rings having dual scraper edges, whereby a seal ring is produced with an outer scraper lip spaced inwardly of the outer peripheral surface of the seal ring body and with the annular surface between the scraper lip and peripheral surface tapering away from the scraper lip toward the peripheral surface. This seal ring configuration, when in use, defines between the housing end wall and the seal ring an annular chamber of wedge shape, in cross section, which chamber functions to cause the oil to exert a hydrodynamic force on a portion of the seal ring and thereby cause that portion of the scraper edge to lift off the housing end wall and the oil in the chamber to flow inwardly past the outer scraper edge.

SUMMARY OF THE INVENTION This invention thus contemplates a method of producing an oil seal ring, having two spaced, concentric, annular, scraper lips or edges, comprising the step of disposing a flan or blank of flat sheet material between the fixed die face and a complementary movable die face of a stamping and forming device, squeezing the flan or blank between the fixed and movable die faces to deform the flan to form two annular concentrically spaced raised portions and substantially simultaneously cutting or punching out two spaced concentric rings to form the inner and outer peripheral surfaces of the seal ring.

In a narrower aspect of the present invention, the method includes the step of forming the outer scraper edge inwardly of the outer peripheral surface of the seal ring by partial shearing deformation of the flan.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood from the fol lowing description when considered in connection with the accompanying drawings in which:

FIG. 1 is a schematic cross-sectional, fragmentary view of a stamping and forming device which may be employed to carry out the method according to this invention;

FIG. 2 is a plan view of the oil seal ring produced by the method according to the present invention;

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2 and on an enlarged scale; and

FIG. 4 is a fragmentary view, in cross-section, showing the oil seal ring fabricated according to this invention assembled in a rotary piston mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION Now referring to the drawings and, more specifically FIG. 1, 10 generally designates a coining and punching device which may be employed to produce an oil seal ring 12 (see FIGS. 2 and 3) according to the method of the present invention. A flan, planchet or blank 14 of sheet material and of substantially the thickness of the seal ring to be fabricated is positioned between and against the face 16 on a stationary die portion 18. The stationary die portion 18 has an annular recess 20 in face 16, the bottom portion of which is shaped to provide two annular concentric apices 22 and 24 formed by annular, inclined surfaces 26 and 28 and respectively intersecting annular, vertical surfaces 30 and 32. A movable die portion 34, including spaced, concentric cutters or blades 36 and 37, is disposed adjacent to and in axial alignment with die portion 18. Conventional means (not shown) is provided for reciprocatively actuating movable die portion 34 relative to stationary die face 16. The movable die portion 34 has an annular die face 38 having a configuration substantially complementary to die face 16. More specifically, die face 38 has two spaced annular, inwardly tapering surfaces 40 and 42 which are complementary to inclined surfaces 26 and 28 of die face 16.

After placing blank 14 on die face 16, die portion 34 is next actuated to abut blank 14 and squeeze the blank within annular recess 20 and thereby cause the blank to deform and plasticly flow into the configuration established by the shape of the recess 20 and die face 38.

Substantially, simultaneously with the aforesaid coining or stamping operation, blades 36 and 37 are driven relative to die faces 16 and 38 into annular slots 44 and 45, respectively, in stationary die portion 18 to punch-out or cut the blank 14 to form the inner and outer peripheral surfaces 46 and 48 of the resultant oil seal ring 12 (shown in broken lines in FIG. 1 and in full lines in FIGS. 2, 3 and 4). As can be readily understood from the illustration in FIG. 1 and as shown in FIGS. 2 to 4, the recess 20 in die face 16 and die face 38 cooperate to form two annular concentrically spaced, annular, scraper edges or lips 50 and 52 on the oil seal ring 12. The scraper edge 52 is created at the intersection of an annular inclined surface 53 and inner peripheral surface 46 while scraper edge 50 is formed by the intersection of an inclined, annular surface 54 and an annular, vertically extending wall 56.

Preferably, as is illustrated in the drawings, scraper edge 50 of oil seal ring 12 if formed inwardly of the outer peripheral surface 48 by locating annular, vertical surfaces 30 in recess 20 and a complementary annular, vertical surface 60 on die face 38 inwardly of the outer peripheral surfaces of their respective die portions. These two vertical surfaces 30 and 60 coact with inclined surfaces 26 and 40 to cause scraper edge 50 to be formed along a shear line. It also serves, as best illustrated in FIG. 4, to provide oil seal ring 12 with annular inclined surface 54 which in use defines with a rotary piston housing side wall 64, an annular chamber 66. The inclined surface 62 gives chamber 66 a wedgelike cross-sectional shape so that the oil imposes a hydrodynamic force on a portion of the seal ring to cause that portion of scraper edge 50 to lift off housing side wall 64 thereby permitting leakage oil in the chamber 66 to flow past scraper edge 50 and away from the gas seals (not shown).

Thus, the method, according to this invention as herein described, provides a relatively quick, simple and inexpensive means of producing an oil seal ring having dual, concentrically spaced, scraper edges. It is also a method by which the outer scraper edge of the fabricated oil seal ring is defined by the intersection of a vertical wall spaced inwardly of the peripheral surface and an annular surface inclined in a direction away from the plane of the scraper edges.

Although, but one embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the arrangement of parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

What is claimed is:

1. The method of manufacturing an oil seal ring for a rotary piston mechanism comprising the following steps:

a. disposing a blank of material out of which an oil seal ring is to be made between the stationary and movable annular die faces of a coining and punching device;

b. deforming the blank into an annular shape having at least one annular edge portion projecting beyond the surface of the oil seal ring being fabricated by squeezing the blank between the annular die faces, and

c. substantially simultaneously punching out two concentrically spaced portions of the blank adjacent the deformed portion to form the inner and outer peripheral surfaces of the oil seal ring.

2. The method of claim 1 wherein said at least one annular edge portion is formed by imposing on the blank a shearing stress.

3. The method of claim 1 wherein the blank is deformed to create two annular, concentrically spaced edge portions lying in substantially the same plane spaced from the other surface portions of the oil seal ring.

4. The method of claim 3 wherein one of the two annular edge portions is formed by deforming the inner annular area of the oil seal ring being fabricated to provide an annular inclined surface and punching out the inner portion of the blank to intersect the inclined surface and form the inner peripheral surface of the oil seal ring. 

1. The method of manufacturing an oil seal ring for a rotary piston mechanism comprising the following steps: a. disposing a blank of material out of which an oil seal ring is to be made between the stationary and movable annular die faces of a coining and punching device; b. deforming the blank into an annular shape having at least one annular edge portion projecting beyond the surface of the oil seal ring being fabricated by squeezing the blank between the annular die faces, and c. substantially simultaneously punching out two concentrically spaced portions of the blank adjacent the deformed portion to form the inner and outer peripheral surfaces of the oil seal ring.
 2. The method of claim 1 wherein said at least one annular edge portion is formed by imposing on the blank a shearing stress.
 3. The method of claim 1 wherein the blank is deformed to create two annular, concentrically spaced edge portions lying in substantially the same plane spaced from the other surface portions of the oil seal ring.
 4. The method of claim 3 wherein one of the two annular edge portions is formed by deforming the inner annular area of the oil seal ring being fabricated to provide an annular inclined surface and punching out the inner portion of the blank to intersect the inclined surface and form the inner peripheral surface of the oil seal ring. 